Process for cracking petroleum oil



May 15, 1928. 1,670,103

c. P. DUBBs PROCESS FOR CRACKING PETROLEUM OIL Original Filed Patented May 15, 192.8.

UNITED [STATT-:sv

y 1,670,103 PATENT OFFICE.

CARBON P. DUBBS, F XILMETTE,v ILLINOIS, ASSIGNOR T0 THE UNIVERSAL OIL PRODUCTS COMPANY, OIE CHICAGO, ILLINOIS, A CORPORATION 0F SOUTH DAKOTA.

PROCESS EOR'CRACKING PETROLEUM oIL.

Application led March 9, 1923, Serial No. 623,988. Renewed .Tune 15, 1927.

This invention relates to a process for cracking petroleum oil, and refers more particularly to that type of process in which the oil is passed through a suitable heating furnace preferably in -a relativelysmall stream, as for example, through a preheating coil and the'nce to an expansion chamber where vaporization takes place, and a separation is made of the vapors and resi- .0 due.

It is of course, known to those skilled in the art,.that one of the principal difficulties in the cracking process heretofore, has been in the handling of the carbon containing residue in such a manner. as to obtain a maximum yield of gasoline without all too often having to shut down the plant because of it becoming choked with carbon or because of hot spots developing from' carbon, or the apparatus being subjected fires or danger of explosion.

At the same time the cracking process is in its last analysis one of economy, namely being able to make the desiredgasoline or other product with a minimum cost. To do. this, it is desirable to crack as large a percentage of the oil into gasoline as is practicable. Accordingly, it is desirable to retreat the residue, but care must be taken not to retreat the residue in such quantities and of such a character as tochoke upthe heating tubes. Also different kinds of oils must be treated in a different manner, and it is obvious that the average small inde- ;5 pendent refiner cannot aord to build a cracking plant for each separate oil he has to treat, due to the various crudes or the different cuts of` the crude as for example, kerosene, gas oil and fuelY oil. Y

lTo this end, itis desirable to have an apparatus and process which will have as much flexibility asl is possible, bearing in mind the necessity of retaining the economy in operation and simplicity of construction. The object of the invention is to give the independent or small reiiner such a process and apparatus, and it may here now be stated that the process hereinafter described is inno sense necessarily confined to the particular type of apparatus hereinafter set forth, although I believe that the apparatus itself contains substantial patentable noveltv.

In order tovundersytand the invention, I have shown theaccompanying drawing in ysure may be maintained on the tanks.

which the single figure is a somewhat diagrammatic representation of my improved fapparatus, and I also wish to state that 'the are too well known to those skilled in the art to necessitate any detailed description at this day.

Referring to the drawing, 1 designates a furnace in which is mounted the heating coil 2 which may take the form of a plurality of two to six inch tubes, preferably connected in series, although if desired, the coils may be connected in multiple. The oil enters the heating coil through the charging line 3 having a throttle valve 4 connected to the feed pump 5, the inlet side lof the pump being connected'to pipe 6 having a throttle valve 7 to storage tank 8, hereinafter referred to.

The oil heated to the desired temperature,

"passes through. transfer line 8f having throttle valvev 9 into the first of a series of tanks 10, 11, 12 and 13 respectively. These tanks are connected by the liquid overflow lines 14 each having suitable throttle valves 15 whereby if desired, a differential prpe tanks may also be provided with vapor connection pipes 16, 17 and 18 having suitable throttle valves 19, 20 and 21 respectively.

Instead of passing the vapors serially through the tanks, they may be taken off .from the top of each tank through pipes 22 controlled by throttle valves 23, the pipes 22 leading to a manifold pipe 24 having a. throttle valvel 25 and connected to the'vapor pipe 26 leading from the top of the last tank 13. The pipe 26 communicates with the lower end of the dephlegmator, and may be provided with a throttle valve 28, if desired. The upper end of the pipe 26 1s covered with a spaced cap member 29, the arrangement being such as to permit vapors `to enter the lower end of the dephlegmator 27 whilev preventing the reiiux condensate from falling back into the chamber 13. As the vapors enter the dephlegmator 27, they are subjected to a reux condensing action and the reiiux 'condensate is drawn ofi' through the pipe 30 controlled by a throttle valve 31 back to the feed line 3. The uncondensed vapors pass out ofthe top of the dephlegmator through the pipe 32 con-l trolled by the throttle valve 33 to the water condenser 34 connected to lthe receiver 35, which receiver is equipped with gas outlet pipe 36 having a throttle valve 37 and a liquid drawoff pipe 38 having a throttle valve 39.

kThe arrangement is such that a uniform pressure may be maintained on the system or a differential pressure may be maintalnedlby regulating the valves shown.

Referring now particularly to the tanks to 13 inclusive, they may be insulated and located entirely outside ofthe lire zone, or if desired. they may be located in a suitable iire setting 40 where they may be heated as a whole, or they may be individually heated by suitable burners, not shown, so as to have a uniform temperature in the tanks, which temperature may be gradually increased or decreased depending upon conditions.

Referring now more particularly to the manner of handling the residue in these tanks, as heretofore stated the character of the residue will vary with the extent to which the process is pushed, the character of the oil treated, as for example, whether it has a paraffin base or an asphaltic base, and also upon the particular cut of the oil from any of these crudes which may be taken.

It .may therefore be desirable to retreat part 'ot the residue but not necessarily all of it, and it may be desirable to make rather tine differentials as to what particular type 5 of the residue it is desired to treat.

To this end the tanks 10, 11, 12 and 13 are provided with liquid d-rawoi' lines 41 each controlled by suitable throttle valves Q42, which may lead to a suitable manifold pipe 43 having a throttle valve 44 and leading to a combined storage and settling tank 45, which tank 45 is provided with a suitable overiiow pipe 46 having a valve 47 whereby the residue may be delivered in regulated quantities to the storage charging tank 8. The tank 45 may have acarbon drawoi'pipe '448 controlled by a valve 49, whereby the heaviest part of the residue may, if desired,

be prevented from entering the tank 8. As

' shown clearly in the drawing, the residue from any of the tanks 10, 11, 12 or 13 may be by-passed and prevented from -entering the tank 45 bymeans of by-pass lines 50 each having a throttle valve 51. While, it is of course desirable to recrack as much of the residuum as possible, it is also desirable to so regulate the character of the residue' and the iantity of it relative to the raw oil charg ng stock to secure the most effective results.

It is apparent that this canbe accomplished very readily by means of the method and apparatus above described. The combined charging stock may be lfed by means of the pump 5 ,and the line 52 having a ch arging stock.

throttle valve 54 to the upper end of the dephlegmator, where it serves to cool the vapors and at` the same time preheat the The combined reflux condensate and charging stock may be drawn olf through the pipe 30 and passed to the tubes. If desired, however, the dephlegmator may be bypassed as far as the charging stockis concerned, and the latter delivered direct by the pump 5 through the feed line 3/to the coil 2, the valve 54 in the line 52 being then closed.

In carrying out the process, the oil may be subjected to a pressure of from 10() pounds upwards, if desired, and the oil so cracked as to convert from to'7 5% or more into gasoline of say 400 end point.

The extent to which the cracking takes place, and the amount of total gasoline cracked, can be very effectively means of the present invention.

I claim as my invention:

1. A process for cracking oil consisting in passing the oil through a heating coil,

BISj regulated 'by f thence to a plurality of enlarged chambersl connected in series and allowlng vaporization to take place in said chambers and withdrawing the vapors therefrom, withdrawing the liquid residue from each of said chambers independently and diverting predetermined quantities of said residue from predetermined chambers back to the chargin stock and .commingling the same with sai charging stock and sendin said mixture through the heating coil to e cracked and maintaining a superatmospheric pressure on the oil durmg treatment.

2. A process for cracking oil consisting in passing the oil'through a heating, zone preferably in a relatively small stream, thencepto a plurality of enlarged chambers connected in series and allowing vaporization to take place in said chambers and withdrawing the vapors therefrom, withdrawing the .li uid residue from each of said chambers independently and diverting predetermined quantities of said residue from predetermined chambers back to the charging stock and commingling the same with said charging stock and sending said mixture through the said heating zone to be cracked and maintaining a super-atmospheric pressure on the oil during treatment.

ing predetermined quantities of said residue from predetermlned chambers back to the charging stock and commingling -the same wth said charging stock and sending said mixture through the heating zone to be cracked, and maintaining a super-atmospheric pressure on the oil during treatment.

4. A process `for cracking oil consisting in passing the oil through a heatingV coil, thence to a plurality of enlarged chambers connected in series, the temperature o fsaid chambers being controlled relative to the temperatures in the heating coil, and allowing vaporization to take place in said cham# bers, and withdrawing ythe vapors therefrom, withdrawing the liquid residue from each' of said chambers independently and divertin predetermined quantities of said residue gram predetermined chambers back to the chargin stock and commin ling the same with sai charging stock an vsending said mixture through the heating coil to be cracked and maintaining a superatmospheric pressure on the oil durmg treatment.

5. A process for cracking oil' comprising passing the oil through a heating zone; thence to a plurality of enlarged zones arranged in series, controlling the temperature ofy said enlarged zones relative to the temperature of the heating zone, effecting vaporization of oil constituents in said enlarged zones, removing the vapors therefrom, selectively withdrawing liquid residue from each of said enlarged zones, diverting predetermined portions of the liquid residue withdrawn from predetermined enlarged zones back to the heating zone to commingle with charging oil for the process and be subjected to further crackin and maintaining controlled superatmosp eric I ressure on the oil undergoing treatment in t e process.

CARBON P. DUBBS. 

